An integrated circuit (also referred to as IC, chip, or microchip) is an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material. Additional materials are deposited and patterned to form interconnections between semiconductor devices.
ICs were made possible by experimental discoveries showing that semiconductor device could perform the functions of vacuum tubes and by mid-20th-century technology advancements in semiconductor device fabrication. The integration of large numbers of tiny transistors into a small chip was an enormous improvement over the manual assembly of circuits using discrete electronic components. The integrated circuit's mass production capability, reliability, and building-block approach to circuit design ensured the rapid adoption of standardized ICs in place of designs using discrete transistors.
In the early days of integrated circuits, only a few transistors could be placed on a chip, as the scale used was large because of the contemporary technology, and manufacturing yields were low by today's standards. As the degree of integration was small, the design was done easily. Over time, millions and today billions, of transistors could be placed on one chip, to make a good design become a task to be planned thoroughly.
ICs have consistently migrated to smaller feature sizes over the years, allowing more circuitry to be packed on each chip. In general, as the feature size shrinks, almost everything improves—the cost per unit and the switching power consumption go down, while the speed goes up. However, ICs with nanometer-scale devices still incur their original problems, principal among which is leakage current, although these problems will likely be solved or at least ameliorated by the introduction of high-k dielectrics.
Semiconductor ICs are fabricated in a layer process which includes these key processes: deposition, patterning, removal, and modification of electrical properties.                Deposition is any process that grows, coats, or otherwise transfers a material onto the wafer. Available technologies comprising physical vapor deposition (PVD), chemical vapor deposition (CVD), electrochemical deposition (EPC), molecular beam epitaxy (MBE) and more recently, atomic layer deposition (ALD) among others.        Patterning covers the series of processes that shape or alter the existing shape of the deposited materials and is generally referred to as lithography. For example, in conventional lithography, the wafer is coated with a chemical called a photoresist. The photoresist is exposed by a stepper, a machine that focuses, aligns, and moves the mask, exposing select portions of the wafer to short wavelength electromagnetic radiation. The unexposed regions are washed away by a developer solution. After etching or other processing, the remaining photoresist can be removed by plasma ashing.        Removal processes are any that remove material from the wafer either in bulk or selectively and consist primarily of etch processes, either wet etching or dry etching. Chemical-mechanical planarization (CMP) is also a removal process used between levels.        Modification of electrical properties has historically comprising doping sources and drains of a transistor originally by diffusion furnaces and later by ion implantation. These doping processes are followed by furnace anneal or in advanced devices, by rapid thermal anneal (RTA) which serve to activate the implanted dopants. Modification of electrical properties now also extends to reduction of dielectric constant in low-k insulating materials via exposure to ultraviolet light in UV processing (UVP).Modern chips have up to eleven metal levels produced in over 300 sequenced processing steps.        
In order to achieve the setting yield, the yield management of a fab needs to monitor, classify, eliminate or avoid defects from all kind of processes. A wafer map analysis has been developed for detecting and classifying patterns or process signatures based on low-resolution (e.g., 0.5 μm/pixel) optical defect image distribution. As wafers exit a fabrication process, wafer map data is generated by an in-line defect detection workstation incorporating a microscopy or light-scattering system. The information in the wafer map consists of detected defect coordinates as well as process information such as step, layer, and product. The wafer map data may be combined across wafers to further view the evaluation of process signatures which may assist in diagnosing manufacturing problems.
As the feature size shrinks, ICs yield improvement by defect reduction becomes more and more important. A pre-analysis of signatures of a process or a structure with computer workstation starts with using graphical database system (GDS) to construct photomask far a die, then to utilize the computational lithography to numerically simulate, and to improve the performance (resolution and contrast) of cutting-edge photomasks. Next optical proximity correction (OPC) process is introduced in the modern semi con due tor manufacturing. The OPC uses computational methods to counteract the effects of diffraction related blurring and under-exposure by modifying on mask geometries with means:                Adjusting line-widths depending on the density of surrounding geometries (a trace surrounded by a large area will be over-exposed compared with the same trace surrounded by a dense pattern).        Adding “dog-bone” end caps to the end of lines to prevent line shortening.        Correcting for electron beam proximity effects.The computer-aid pre-analysis will illustrate a possible defect distribution positions within the IC which is named “hot spots” to the ICs yield management.        
As a part of the wafer map process, an off-line defect review station examines these hot spots with a high resolution microscope, e.g., a defect inspection/review tool comprising scanning electron microscope (SEM), and classifies the defect according to individual morphology, color, texture, and relationship to process or layer.
The defect inspection/review tool proceeds wafer inspection/review job according to a process instruction called a “recipe”. A “recipe” is a set of operating instructions (a processing program) that educates a tool how the tool should perform the process. The recipe varies for each kind of machine, and even among different machine manufactures for the same kind of machine. For example, an etch system by Applied Materials of Santa Clara, Calif. may require a 10-minute reaction time with a certain flow of gases, while the reaction chamber is kept at a certain, elevated temperature. At the end of the 10-minute reaction time, the flow of reactive gases is gradually reduced and replaced with inert gases as the temperature is lowered. Another etch system by Lam Research of Fremont, Calif. may require a 15-minute reaction time, with a different mixture of gases and a different temperature. Other kinds of semiconductor processing equipment require vastly different recipes. These recipes can become quite complex and vary as process engineers attempt to tweak the process for desired electrical and manufacturing-yield results. Different semiconductor products may require different recipes or combinations of steps. A DRAM process may require lighter ion implant doses than a process for logic chips and different oxide thicknesses require different reaction time in the furnace.
The recipe for a defect inspection/review tool contains instructions such as (a) product information that record the current inspection is after what semiconductor process; (b) inspection parameters that set the inspection tool, detecting area; and (e) detecting parameters that instruct the tool what to do in the detecting area. As an SEM-based defect inspection/review tool provides images at high resolution (e.g., 0.01 μm/pixel), however, the throughput of a fully examined wafer (e.g., 24 hours/wafer) is away below the expectation (e.g., 1 wafer/hour).
The wafer map analysis illustrates defects distribution after processing, in which the defect clustering area on the wafer is called “weak points” of the wafer. In order to meet the throughput requirement, a recipe instructs the inspection/review tool to perform the inspection according to the weak points might be a solution.
The present invention provides a weak point inspection method performed by a charged particle beam inspection/review tool to meet the throughput requirement in semiconductor manufacturing.